thanks! CA now removed from "fy", but I'm in two minds whether to add the BA domestics as "jy" instead of the current "y". It depends whether being accurate as far as the points/miles is better, or setting the right expectations for the lack of onboard J. (the "Business UK" fare does permit lounge access, so all that's missing is the separate cabin onboard)
Given the way this data is being used in MM, I would opt for showing these flights as jy, which, as you say, would give more accurate figures for miles/points.
The lack of J cabin in Domestic isn't all that different from the CE situation, bar curtains and 'catering'.